These rust and scratch stickers are designed to make your beautiful bike/car look rusted and scratched so that passing thieves assume it's not worth stealing due to its apparent shabbyness.
Note. This anti-theft device is not guaranteed to work in any way.
However I have stuck them to my shiney new red bike and can confirm it hasn't been stolen yet. 13 days of not being stolen in London probably equates to 7 years of non-stealing in the friendly countryside.
More info email here